Why do I need my spouse information on my taxes she is following her own

[SweetieJean]

Do you live in a Community Property State?

[LindaA]

The IRS requires you to include your spouse's full name and Social Security Number (SSN) on your tax return when your filing status is married filing separately. (Click the screenshot below to enlarge it for reference.)

[SweetieJean]

If one of you itemizes, you both must. This is how the IRS checks that.